# 範例2
## 一般印數字
ClassDemo01.java(下稱建構子區)
```java=
public class ClassDemo01 {
public int getNumber() {
return new Inner().setNumber() + 100;
}
// 內部類別
private class Inner {
private int a = 123;
public int setNumber() {
return a;
}
}
}
```
MainTest.java(下稱測試區)
```java=
public class MainTest {
@Test
public void test01() {
ClassDemo01 cd = new ClassDemo01();
int z = cd.getNumber();
System.out.println(z);
}
}
```
## 輸入一個字元做選擇
建構子區
```java=
public class ClassDemo01 {
public int getNumber(char x) {
if (x == 'A') {
return new Inner().setNumber();
} else if (x == 'B') {
return new Inner().setNumber1();
} else if (x == 'C') {
return new Inner().setNumber2();
} else {
return 0;
}
}
// 內部類別
private class Inner {
private int a = 123;
public int setNumber() {
return a;
}
public int setNumber1() {
return a + 23;
}
public int setNumber2() {
return a + 100;
}
}
}
```
測試區
```java=
public class MainTest {
@Test
public void test01() {
ClassDemo01 cd = new ClassDemo01();
int z = cd.getNumber('A');
System.out.println(z);
}
}
```